Preassembled impedance unit



May 31, 1949. D. H. MITCHELL PREASSEMBLED IMPEDANCE UNIT Original FiledFeb. 20, 1 942 florzald Patented May 31, 1949 "PREASSEMBLED IMPEDANCEUNIT IDonald-H. Mitchell; Chicago, Ill., .assignor to Motorola; 1110., acorporation of Illinois Original application February 20; 1942,SerialNo. 1 431,722. "Divided and this application February 21; 1945;Serial-No. 579,003

. 2 Claims.

.This: invention relates topreassembleddmpedanceunitspf thetype-suitable for, usea-as; a

componentmofi an. electrical apparatus .having connection: terminals;arranged. in a; generally arcuate path; and; while itsis; of general.applica- :tion,: it: is particularly suitable for embodiment in a .nnitto belmounted: directly on. the. base; of a vacuum-tube: socket: and; isdescribeduherein :ln

such anapplication. This::application isiaydivision of copendingapplication, :5 Serial 'No. 431,722,:fi-led February '20, 1942,United;.States Patent 2,439,408, and entitled Portableradio de- 'vice.

- 'Itis well'knownthat radio apparatus generally comprises a chassis 'or.framermembenaon "which are mounted a numbenoi vacumnetube sockets:iorwreceivlngr replaceablevacuum: tubes and a is also well known thatthe assembly of such radio apparatus is generally done by relativelyunskilled employees, Which tends to aggravate all of .the'iactorsdiscussed.

' It is anobject of the invention, therefore, to provide a new andimproved.preassembledsim- :pedance unit by means of which one or. moreof the above-,mentioned problems ot assembling radio cit-otherelectrical apparatus may. besatisiactorilysolved.

It is another object of :the-inventiontorprovide a new and improvedpreassembled impedance unit which permits'preassembly by automaticmachinery of a substantialportion of the-circuit elements of electricalapparatus; such as resistors,

condensers and inductors comprised in the apparatus.

It is a further object of the invention to provide a new and improvedpreassembled impedance unit which is simple and compact and economicalin construction and by means of which the lengths of the connectingconductors required in the wiring of associated electrical apparatus maybe reduced to a minimum.

In accordance with the invention a preassembled impedance unit for useas a component of an electrical apparatus having connectionterminalsarranged in a'generally arcuate path comprises a generally cylindricalcontainer and aplurality of impedance elements of predeterminedyalues'fixedly. arranged around the periphery-of the container andinsulatedly supported thereirom and having'connection terminalsextending therefrom. The connection terminals of the :unit are arrangedto be disposed lu -proximity totheir respective connection terminalsof-the apparatus.

For a better understanding of the invention, together with other andfurther objects thereof, reference is had to the following descriptiontaken in connection with the accompanyingdraw-ings while itsscope willbe pointed out in the appended claims.

Referrin now to the. drawings, Fig." 1': isian exploded perspective viewof a preassembled/impcdance unit embodying the invention;- Fig. 2-isacross-sectional view of the -,apparatus of Fig: .1; llig. 3 isalongitudinal section of the2device-of Fig.- 1 as applied to avacuum-tube socketywhile Figs.- 4 and- 5 are top and side views,respectively, :of 'thewassembled: device of Fig. 1.

:iReierring; nowto-Figs; l and 2 of the drawings, therel-isiiillustrated a preassembled' impedance unit for use as a component of, anelectricalapparat. 1,1such, as a'vacuum-tube socket 94-;havinga c;dric-alr: body portionv -92 and a: plurality of connection terminals:98' arrangedinv a generally arcuate path concentric Withthe body portion'32 and projectin fromone end: o-f-the socket. "The :impedanceiunitCOnSlStS'LOfa' generally cylindrical preferably annular, open-endedcontainer :inernber Q i of' insulationmaterial and. of chan--.nel:-;shaped: cross section; the. open.a,:end.;thereoi being 'closedor; sealed by ayflat ringeshaped closure :member; its of: insulationmaterial such as: fibre. Around the. periphery. :oflthe container l 0. lthat is Within :the. annularrchannel thereof, are; fixedly arranged a.-.plurality .of impedance 9.816- ments such asresistors'Rland condensersC,.tvhich are of predetermined values. and electrically :connectedritogether. in a predetermined circuit. arrangement to provide the desiredcircuit characteristics for the associated apparatus, for example a tubeT1 disposed in the socket (Fig. 3). Connections I05 for connecting theresistors and condensers to the connection terminals 98 extend outwardlyfrom the impedance unit 99 through the bottom wall thereof.

Usually not all of the connections from the impedance unit are to beconnected with the socket connection terminals 98 but some of them areto be connected to other portions of associated apparatus. These otherconnections, therefore, are in the form of connection lugs lll5a (Figs.4 and 5) secured to the container member Hi! to facilitate theirconnections With any other part of the associated apparatus. With thecondensers C and resistors R in position within the container member595, a mass of suitable impregnating insulation material, such as Wax orthe like and indicated at W, is disposed in the container l M forexample poured into the upper open end thereof, the hardening of the Waxembeddin the elements, retaining them in fixed positions, and protectingthem against any short circuiting or exposure to the atmosphere. Theclosure member W3 is then glued or otherwise suitably secured tn theopen end of the container llll. To facilitate the connection of theimpedance unit 99 to its associated circuit elements and to indicate themar ier in which the resistor and condenser elements are connectedtherein, a circuit diagram for the unit, indicated at I (Fig. is appliedon the cuter periphery of the container NH.

The impedance unit 99 also includes provisions for mounting it from thecylindrical body portion of an associated electrical apparatus andconcentric therewith. Specifically, its inner opening is proportioned sothat it may be mounted and fitted directly on the body portion 92 of thecylindrical tube socket 9 3. As indicated in Fig. 3, the socket 94 issupported from a chassis or frame member 89 and it is adapted to receivea tube T1 and to support a cylindrical shield can Hi.

In the assembly of the impedance unit 99 on the tube socket 94, thesoldering of the connections I05 with the connection terminals 98 of thesocket 94 holds the impedance unit 99 in a fixed assembled position onthe socket. In order to retain the impedance unit 99 in the assemblyposition during the soldering operation, it may be cemented or glued tothe chassis 89 or to an associated element thereof. The elements withinthe unit 99 are so arranged that, when the unit 99 is mounted in anassembly position on the socket 94, the connection terminals I05extending therefrom are arranged in proximity to their respectiveconnection terminals 98 of the tube socket. With this arrangement theinterconnection of the impedance unit 99 and the tube socket 94 is ofmaximum simplicity and the connection leads are as short as possible.

Although the impedance unit of the invention has been described withreference to a particular application thereof, it is readily apparentthat it is not limited to this one application but can be constructedwithin the scope of this invention for use generally as a component ofelectrical apparatus. Considerable difficulty is usually encountered inhandling and assembling of the condenser and resistor elements in aradio apparatus. By virtue of the compact and insulated assembly of theelements in the impedance unit 99, this unit can be convenientlyarranged relative to any desired circuit in which it is used andconnections '4 made therefrom to other portions of such circuit.Individual handling and assembling of the resistor and condenserelements and their connections into the radio circuit is thus entirelyeliminated, thereby decreasing the time usually required in making theconnections and providing for neater appearing and more secureelectrical connections.

While there has been described What is at present considered to be thepreferred embodiment of the invention, it will be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

What is claimed as new is:

1. In an electrical apparatus including one or more electron tubesockets, each of said sockets having a cylindrical body portion adaptedto receive prongs of an electron tube, and a plurality of axiallyextending connection terminals arranged in generally concentric relationto said body portion, a preassembled impedance unit for use as acomponent of said apparatus comprising an annular container having aninner opening of such size as to fit closely about said body portion ofa tube socket, a plurality of impedance elements of predetermined valuesfixedly arranged within said container and insulatedly supportedthereby, and electrical conductors extending from said impedanceelements out of said container, said container having an axial dimensionnot greater than the overall axial dimension of said tube socket bodyportion and said connection terminals, whereby said impedance unit maybe disposed within the axial limits of and surrounding the spaceoccupied by said socket body portion and said terminals.

2. A preassembled impedance unit as defined in claim 1, wherein certainof said electrical conductors leading from said impedance elements arearranged to be disposed in proximity to certain of the connectionterminals of the tube socket with which said unit is associated, so asto facilitate electrical connection thereto.

DONALD H. MITCHELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,589,692 Hiler June 22, 19261,650,754 Kent Nov. 29, 1927 1,656,009 McMullin Jan. 10,1928 1,825,534Mavrogenis Sept. 29, 1931 1,973,248 Evans Sept. 11, 1934 2,111,381Barton Mar. 15, 1938 2,186,184 Tubbs Jan. 9, 1940 2,323,629 Smith July6, 1943 2,377,893 Lorenzen June 12, 1945 FOREIGN PATENTS Number CountryDate 573,514 France Mar. 12, 1924

